1. Field of the Invention
This invention relates to a toner container unit for supplying toner to an electrostatic recording means in, for example, an electrophotographic reproducing machine, in which electrostatic images are developed by the toner into visible images and, more particularly, to an improvement in a toner container unit sealed by a film-like seal member.
2. Description of the Prior Art
Generally, in a dry electrostatic recording means employed a two-component developer or a one-component developer, a certain amount of toner is consumed every time a copy is obtained, therefore it is necessary to supply additional toner after a number of copies have been obtained. The supply of toner is is usually carried out by feeding toner from a toner container unit into a developer receiving means, such as a hopper, in the electrostatic recording means.
The toner is usually in the form of a powder in which the average diameter of the toner particles is between ten and twenty microns. Therefore, the toner can scatter very easily. In particular, when the container is tilted or vibrated, the toner can form a suspended fog in the container.
Accordingly, the toner container unit must have a structure that can prevent positively the suspended toner within the unit from escaping through the opening of the container unit. Further, it is also desirable that the opening of the container unit should have a simple opening structure, so that the opening and closing operation can be attained easily.
In view of these requirements, various kinds of toner container units have been suggested.
One of the toner container units of this kind is a type wherein the opening part is sealed by a film-like sheet which is peeled off after the toner container unit is mounted in the hopper, so that the toner in the unit is fed into the hopper.
A typical structure of this type of toner container unit is disclosed in Japanese Utility Model Laid-Open No. 28,447/1979. According to the disclosed device, the opening part of a container containing additional toner is sealed by a film-like sheet whose rear end is turned back. When the toner container has been mounted in the hopper of the reproducing machine, the extension of the turned-back part of the film-like sheet is pulled by hand so as to peel the sheet off from the container unit, so that the toner therein can be fed into the hopper as required.
Another typical structure of toner container unit is disclosed in Japanese Utility Model Laid-Open No. 99,545/1980, in which the opening part of the toner container unit is also sealed by a filmlike sheet which is turned back at the rear end. In this device, the extension of the turned-back part of the sheet is secured to one end of the hopper of the reproducing machine. During the process of inserting the toner container unit into the hopper, the sheet peels off by itself, so that the toner can pass through the exposed opening part.
All of these toner container units described above have a common point in that the opening part is sealed by a film-like sheet. This sealing can provide a good sealing effect so long as the toner is within a sealed container. However, once the opening part is exposed by peeling off the film-like sheet in order to supply the toner to the hopper, or by removing the toner container unit from the hopper in order to replace it with a new one, toner attached to the sheet and opening part of the toner container unit or remaining in the unit can easily be scattered into the surroundings of the reproducing machine and onto the body of the operator.